Everter and threadthrough system for attaching graft vessel to anastomosis device

ABSTRACT

An everter and threadthrough system useful for attaching a graft vessel to a anastomosis device which can be used to attach a graft vessel to a target vessel without the use of conventional sutures. The threadthrough system engages an end of the graft vessel and pulls the graft vessel through a deployment tool until a portion of the graft vessel extends beyond a distal end of the anastomosis device mounted on the deployment tool. The everter includes a spreading mechanism which expands the end of the graft vessel and folds the expanded end over the anastomosis device. In the case where the anastomosis device includes barbs, the everter can effect penetration of the graft vessel by the barbs. Once the graft vessel is everted over the anastomosis device, the deployment tool can be used to attach the graft vessel to a target vessel.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an everter and threadthrough device forattaching a graft vessel to an anastomosis device which can be used forforming a sutureless connection between a bypass graft and a bloodvessel.

2. Brief Description of the Related Art

Vascular anastomosis is a procedure by which two blood vessels within apatient are surgically joined together. Vascular anastomosis isperformed during treatment of a variety of conditions including coronaryartery disease, diseases of the great and peripheral vessels, organtransplantation, and trauma. In coronary artery disease (CAD) anocclusion or stenosis in a coronary artery interferes with blood flow tothe heart muscle. Treatment of CAD involves the grafting of a vessel inthe form of a prosthesis or harvested artery or vein to reroute bloodflow around the occlusion and restore adequate blood flow to the heartmuscle. This treatment is known as coronary artery bypass grafting(CABG).

In the conventional CABG, a large incision is made in the chest and thesternum is sawed in half to allow access to the heart. In addition, aheart lung machine is used to circulate the patients blood so that theheart can be stopped and the anastomosis can be performed. During thisprocedure, the aorta is clamped which can lead to trauma of the aortictissue and/or dislodge plaque emboli, both of which increase thelikelihood of neurological complications. In order to minimize thetrauma to the patient induced by conventional CABG, less invasivetechniques have been developed in which the surgery is performed throughsmall incisions in the patients chest with the aid of visualizingscopes. Less invasive CABG can be performed on a beating or stoppedheart and thus may avoid the need for cardiopulmonary bypass.

In both conventional and less invasive CABG procedures, the surgeon hasto suture one end of the graft vessel to the coronary artery and theother end of the graft vessel to a blood supplying vein or artery. Thesuturing process is a time consuming and difficult procedure requiring ahigh level of surgical skill. In order to perform the suturing of thegraft to the coronary artery and the blood supplying artery the surgeonmust have relatively unobstructed access to the anastomosis site withinthe patient. In the less invasive surgical approaches, some of the majorcoronary arteries including the ascending aorta cannot be easily reachedby the surgeon because of their location. This makes suturing eitherdifficult or impossible for some coronary artery sites. In addition,some target vessels, such as heavily calcified coronary vessels, vesselshaving very small diameter, and previously bypassed vessels may make thesuturing process difficult or impossible.

An additional problem with CABG is the formation of thrombi andatherosclerotic lesions at and around the grafted artery, which canresult in the reoccurrence of ischemia. The thrombi and atheroscleroticlesions may be caused by the configuration of the sutured anastomosissite. For example, an abrupt edge at the anastomosis site may cause morestenosis than a more gradual transition.

Accordingly, it would be desirable to provide a sutureless vascularanastomosis device which easily connects a graft to a target vessel. Itwould also be desirable to provide a sutureless anastomosis device whichis formed of one piece and is secured to the target vessel in a singlestep.

SUMMARY OF THE INVENTION

The invention provides an everter tool useful for everting an end of agraft vessel over an end of an anastomosis device. The everter toolpreferably includes a mechanism which expands an end of a graft vesseland everts the end of the graft vessel over an anastomosis devicemounted on a deployment tool. For instance, the mechanism can include afirst member having fingers at a distal end thereof, the fingers beingexpandable from a first configuration which fits within the and of thegraft vessel to a second configuration which expands the end of thegraft vessel, and an optional second member cooperating with the firstmember such that the second member is movable from a first location atwhich the fingers are in the first configuration to a second location atwhich the second member expands the fingers to the second configuration.

The everter tool can include various features. For example, the evertertool can be slidably received in a bore of an everter fixture and ahandle on the everter tool can be used to engage a first portion of thehandle with the first member and a second portion of the handle with thesecond member, the handle being movable in an axial direction such thatthe second portion pushes the second member along the first member untila distal end of the second member expands the fingers from the firstconfiguration to the second configuration after which the first portionpushes the first member along the bore until the fingers evert the graftvessel. In such a case, a deployment tool having an anastomosis devicemounted on a distal end thereof and a graft vessel fitted through theanastomosis device can be located in the bore of the housing such thatthe fingers can be pushed into a portion of the graft vessel extendingbeyond an end of the anastomosis device.

In order to locate the graft vessel in the anastomosis device, athreadthrough device can be used for pulling the graft vessel throughthe anastomosis device. The threadthrough device can include a clampwhich attaches to an end of the graft vessel and an extension attachedto the clamp, the threadthrough device being sized to pass through theanastomosis device. The threadthrough device can also include a tonguepivotally connected to the clamp, the clamp being movable towards andaway from the tongue such that the graft vessel can be clamped betweenthe clamp and the tongue. In a preferred embodiment, the threadthroughdevice includes three clamps and the extension comprises a wireconnected to each of the clamps.

According to a preferred embodiment, the anastomosis device includesbarbs for penetrating the graft vessel and the everter tool includes amembrane engageable with the anastomosis device such that the barbspenetrate the graft vessel when the membrane is pressed against theanastomosis device.

The invention also provides a method of everting a graft vessel onto ananastomosis device, the method comprising locating a graft vessel in ananastomosis device mounted on a deployment tool such that a firstportion of the graft vessel is within the deployment tool and a secondportion of the graft vessel extends from an end of the deployment tool,expanding the second portion of the graft vessel, and everting thesecond portion of the graft vessel over the anastomosis device.

The method can be carried out in any suitable manner. For instance, thestep of locating the graft vessel in the anastomosis device can becarried out by attaching an end of the graft vessel to a threadthroughdevice and passing the threadthrough device through the deployment tool.The step of expanding the second portion of the graft vessel can becarried out by inserting an everter tool into the second portion of thegraft vessel. In such a case, the everter tool can optionally be pressedagainst the distal end of the deployment tool until barbs on a distalend of the anastomosis device penetrate the graft vessel. The step ofexpanding the second portion of the graft vessel can be carried out byinserting fingers of the everter tool into the second portion of thegraft vessel and expanding the fingers within the second portion of thegraft vessel. The step of everting the second portion of the graftvessel can be carried out by pressing the everter tool against thedeployment tool. The step of expanding the second portion of the graftvessel can be carried out by locating the deployment tool in a bore ofan everter fixture and sliding the everter tool from a first position toa second position along the bore. The step of everting the secondportion of the graft vessel can be carried out by sliding the everterfrom the second position to a third position along the bore. The step oflocating he graft vessel in the anastomosis device can be carried out bypassing a threadthrough device through the deployment tool, thethreadthrough device having a clamp attached to an end of the graftvessel and a wire extending from the clamp, the wire being pulledthrough an angled hole in the fixture while the graft vessel is pulledthrough the anastomosis device. In such a case, the clamp can bedesigned to spring open after passing out of the anastomosis deviceleaving a segment of the graft vessel extending beyond a distal end ofthe anastomosis device. According to a preferred embodiment, the step ofeverting the graft vessel can be carried out by pressing a first portionof the everter tool against an annular section of the graft vessel andmoving a second portion of the everter tool in contact with an innersurface of the graft vessel until the inner surface is turned inside outover the anastomosis device.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in greater detail with reference tothe preferred embodiments illustrated in the accompanying drawings, inwhich like elements bear like reference numerals, and wherein:

FIG. 1 is a perspective view of a first embodiment of an anastomosisdevice in a configuration prior to use with a graft vessel everted overthe device;

FIG. 2 is a perspective view of the anastomosis device of FIG. 1 in adeployed configuration;

FIG. 3 is a perspective view of an anastomosis device deployment system;

FIG. 4 is an enlarged perspective view of the distal end of theanastomosis device deployment system of FIG. 3 with an anastomosisdevice prior to deployment;

FIG. 5 is a side cross sectional view of the anastomosis devicedeployment system puncturing the target vessel to advance theanastomosis device into the target vessel wall;

FIG. 6 is a side cross sectional view of the anastomosis devicedeployment system advancing the anastomosis device into the targetvessel wall;

FIG. 7 is a side cross sectional view of the anastomosis devicedeployment system with an expanded first annular flange;

FIG. 8 is a side cross sectional view of the anastomosis devicedeployment system expanding a second annular flange;

FIG. 9 is a schematic side cross-sectional view of a deployment tooltaken along line A—A of FIG. 3, the deployment tool is shown during avessel puncturing step;

FIG. 10 is a schematic side cross-sectional view of the deployment toolof FIG. 9 shown during an anastomosis device insertion step;

FIG. 11 is a schematic side cross-sectional view of the deployment toolof FIG. 9 shown during an anastomosis device expansion step;

FIG. 12 is a schematic side cross-sectional view of the deployment toolof FIG. 9 shown after the anastomosis device has been fully deployed;

FIG. 13 shows details of a threadthrough device which can be used in apreferred technique for everting a graft vessel over an anastomosisdevice in accordance with the invention;

FIG. 14 shows how the threadthrough device of FIG. 13 can be passedthrough a deployment tool mounted in an everter fixture;

FIG. 15 shows how an end of a graft vessel can be prepared to be clampedby the threadthrough device;

FIG. 16 shows how the threadthrough device can be passed through afunnel at the back end of a deployment tool;

FIG. 17 shows how tapered grooves in the funnel align and close the jawsof the threadthrough device;

FIG. 18 shows how the jaws can be manipulated to introduce the lumen ofthe graft vessel to fingers of an everter tool after passing through theanastomosis device;

FIG. 19 shows how fingers of an everter tool can be inserted in the endof the graft vessel;

FIG. 20 shows details of the everter tool shown in FIG. 19;

FIG. 21 shows details of an everter fixture;

FIG. 22 shows details of how the graft vessel is expanded;

FIG. 23 shows details of the everter tool shown in FIG. 22;

FIG. 24 shows details of how barbs on the anastomosis device penetratethrough the graft vessel;

FIG. 25 shows details of the graft vessel is everted over theanastomosis device;

FIG. 26 shows the results of the eversion process;

FIG. 27 shows details of the everter arrangement shown in FIG. 26;

FIG. 28 shows the everter tool after separation from the deployment toolhaving the graft vessel everted over the anastomosis device;

FIG. 29 shows details of the everter fixture;

FIGS. 30 and 31 show details of the fixture shown in FIG. 29;

FIG. 32 shows an alternative technique for everting the graft vesselover the anastomosis device;

FIGS. 33A and 33B show another alternative technique for everting thegraft vessel over the anastomosis device;

FIGS. 34A and 34B show a further alternative technique for everting thegraft vessel over the anastomosis device;

FIG. 35 shows a still further alternative technique for everting thegraft vessel over the anastomosis device;

FIG. 36 shows yet another alternative technique for everting the graftvessel over the anastomosis device;

FIGS. 37A and 37B show an additional alternative technique for evertingthe graft vessel over the anastomosis device;

FIGS. 38A and 38B show another alternative technique for everting thegraft vessel over the anastomosis device;

FIGS. 39A and 39B show a further alternative technique for everting thegraft vessel over the anastomosis device;

FIG. 40 shows an alternative technique for everting the graft vesselover the anastomosis device;

FIGS. 41A-E show another alternative technique for everting the graftvessel over the anastomosis device; and

FIG. 42 shows another eversion technique.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to the invention it is possible to perform a variety ofanastomosis procedures, including coronary artery bypass grafting. Theterm “target vessel” is thus used to refer to vessels within the patientwhich are connected to either or both of the upstream and downstream endof the graft vessel. In such procedures, a large vessel anastomoticdevice is used with large diameter target vessels such as the aorta orits major side branches or a small vessel anastomotic device is used fora target vessel which has a small diameter such as a coronary artery.

In deploying a large vessel anastomotic device, the device (with one endof a graft vessel attached thereto) is inserted into an incision in awall of the target vessel with a deformable section in a firstconfiguration, and the deformable section is radially expanded to asecond configuration to deploy a flange. The flange applies an axialforce against the wall of the target vessel. Additionally, the flangecan be configured to apply a radial force, substantially transverse tothe device longitudinal axis, against the wall of the target vessel, tosecure the device to the target vessel. For example, the device can havea plurality of deformable sections forming distal and proximal flanges.With the proximal and distal end flanges deployed, the device can beprevented from shifting proximally out of the target vessel or distallyfurther into the interior of the target vessel.

The large vessel devices can be configured to connect to target vesselsof various sizes having a wall thickness of at least about 0.5 mm, andtypically about 0.5 mm to about 5 mm. In a preferred embodiment of theinvention, the large vessel anastomotic device is configured tolongitudinally collapse as the deformable section is radially expanded.The surgeon can control the longitudinal collapse to thereby positionthe distal end flange at a desired location at least partially withinthe incision in the target vessel wall. The surgeon can also control theposition of the proximal end flange by longitudinally collapsing thedevice to a greater or lesser degree, to thereby position the proximalend flange at a desired location in contact with the target vessel.Thus, regardless of the thickness of the target vessel wall, the devicecan be longitudinally collapsed to position the flanges against thetarget vessel wall and effectively connect the device thereto. Thisfeature is significant because the device must be connected to targetvessels which have a wide range of wall thickness. For example, theaortic wall thickness is typically about 1.4 mm to about 4.0 mm and theaorta diameter can range from about 25 to about 65 mm in diameter.Therefore, regardless of the thickness of the target vessel wall, thedegree of deployment of the proximal end flange, and thus thelongitudinal collapse of the device, can be controlled by the physicianto thereby effectively connect the device to the target vessel. Forexample, the surgeon may choose between partially deploying the proximalend flange so that it is positioned against an outer surface of thetarget vessel wall, or fully deploying the flange to position it incontact with the media of the target vessel wall within the incision inthe target vessel wall.

In deploying a small vessel anastomotic device, the device can be usedon small target vessels having a wall thickness of less than about 1.0mm, and typically about 0.1 mm to about 1 mm in the case of coronaryarteries. Despite the small size of the target vessels, the small vesseldevices provide sutureless connection without significantly occludingthe small inner lumen of the target vessel or impeding the blood flowtherethrough. For example, the small vessel devices can include an outerflange (with the graft vessel connected thereto) loosely connected to aninner flange before insertion into the patient with the space betweenthe loosely connected inner and outer flanges being at least as great asthe wall thickness of the target vessel so that the inner flange can beinserted through an incision in the target vessel and into the targetvessel lumen, with the outer flange outside the target vessel. With theouter and inner flanges in place on either side of a wall of the targetvessel, tightening the flanges together compresses a surface of thegraft vessel against the outer surface of the target vessel. Thisconfiguration forms a continuous channel between the graft vessel andthe target vessel, without the need to suture the graft vessel to thetarget vessel wall and preferably without the use of hooks or barbswhich puncture the target vessel.

In a coronary bypass operation in accordance with the invention, a largevessel device can be used to connect the proximal end of the graftvessel to the aorta, and a small vessel device can be used to connectthe distal end of the graft vessel to an occluded coronary artery.However, in patients with an extreme arteriosclerotic lesion in theaorta, which may result in serious complications during surgicalprocedures on the aorta, the surgeon may wish to avoid this region andconnect the proximal end of the graft vessel to any other adjacent lessdiseased vessel, such as the arteries leading to the arms or head.Further, the devices can be used with venous grafts, such as a harvestedsaphenous vein graft, arterial grafts, such as a dissected mammaryartery, or a synthetic prosthesis, as required.

Connection of the large vessel device does not require the stoppage ofblood flow in the target vessel. Moreover, the anastomotic devices canbe connected to the target vessel without the use of cardiopulmonarybypass. In contrast, anastomosis techniques wherein the aorta is clampedto interrupt blood flow to the area of the aortic wall to which a veinis to be anastomosed may result in liberation of plaques and tissuefragments which can lead to organ dysfunction, such as strokes, renalfailure, or intestinal ischemia. However, severely diseased aortas maynot provide an area suitable for clamping due to significantcalcification of the aortic wall. In the anastomosis technique accordingto the invention, the surgeon does not need significant room inside thepatient to connect the anastomotic devices to the target vessel. Forexample, unlike sutured anastomoses which require significant access tothe aorta for the surgeon to suture the graft vessel thereto, theanastomotic devices allow the proximal end of the graft vessel to beconnected to any part of the aorta. All parts of the aorta areaccessible to the large vessel anastomosis devices, even when minimallyinvasive procedures are used. Consequently, the graft vessel may beconnected to the descending aorta, so that the graft vessel would not bethreatened by damage during a conventional sternotomy if a secondoperation is required at a later time.

According to the invention, a sutureless connection can be providedbetween a graft and a target vessel, while minimizing thrombosis orrestenosis associated with the anastomosis. The anastomotic devices canbe attached to the target vessel inside a patient remotely from outsidethe patient using specially designed applicators, so that the devicesare particularly suitable for use in minimally invasive surgicalprocedures where access to the anastomosis site is limited. The devicesallow the anastomosis to be performed very rapidly, with highreproducibility and reliability, without clamping, and with or withoutthe use of cardiopulmonary bypass.

According to one preferred method of deploying the anastomosis device,the surgeon operates a deployment tool using both hands. One handsupports the tool via a handle while the other twists an actuation knobto deploy the anastomotic device. Locating the actuation knob on thetool's main axis minimizes the tendency of reaction forces to wobble thetool keeping it stable and in proper position during deployment. Thetwisting motion is converted to linear displacements by a set ofrotating cams that engage a trocar, holder, and expander. The camscontrol the sequence of relative motions between the instrument's trocarand device deployment mechanisms.

During the foregoing procedure, a surgeon will place the tip of theinstrument (the mechanical stop) in light contact with the site on theaorta to be anastomosed. Having located a suitable site, the surgeonthen twists the actuation knob to fire the spring-loaded trocar andcontinues twisting to deploy the anastomotic device. The trocarpenetrates the aortic wall at a high rate of speed to minimize anyunintended deformation of the aorta and maintains a substantiallyfluid-tight seal at the puncture site. Having entered the aortic lumen,the trocar dilates as the anastomotic device and its holder tube (crown)are advanced through it, thus retracting the aortic tissue and servingas an introducer for the device. Once the device has fully entered theaortic lumen the trocar is withdrawn. The anastomotic device is thenexpanded to its full diameter and an inner flange is deployed. Thedevice is then drawn outwards towards the instrument (mechanical stop)to seat the inner flange firmly against the intimal wall of the aorta.An outer flange is then deployed from the external side, compressing theaortic wall between the inner and outer flanges and the device isdisengaged from the instrument completing the anastomosis.

FIG. 1 illustrates the distal portion of an anastomosis device 10according to a first embodiment of the present invention, the proximalportion (not shown) being adapted to be deployed by a deployment toolwhich will be explained later. The anastomosis device 10 includes aplurality of axial members 12 and a plurality of struts 14interconnecting the axial members. The axial members 12 and struts 14form a first linkage 16 at a first end of the device and a secondlinkage 18 at a second end of the device. The first and second linkages16, 18 form inner and outer flanges 20, 22 when the anastomosis device10 is deployed as illustrated in FIG. 2. The deployed flanges 20, 22 maybe annular ring shaped or conical in shape. The first and secondlinkages 16, 18 are connected by a central connecting portion 24.

In use, a graft vessel 30 is inserted through a center of the tubularanastomosis device 10 and is everted over the first linkage 16 at thefirst end of the device. The first end of the device may puncture partway or all the way through the graft vessel wall to hold the graftvessel 30 on the device. An opening 34 is formed in the target vessel 32to receive the graft vessel 30 and anastomosis device 10. Once theanastomosis device 10 with everted graft vessel 30 are inserted throughthe opening 34 in the target vessel 32, the inner and outer flanges 20,22 are formed as shown in FIG. 2 to secure the graft vessel to thetarget vessel by trapping the wall of the target vessel between the twoflanges. The anastomosis device 10 forms a smooth transition between thetarget vessel 32 and the graft vessel 30 which helps to prevent thrombiformation.

The inner and outer flanges 20, 22 are formed by radial expansion of theanastomosis device 10 as follows. The first and second linkages 16, 18are each made up of a plurality of axial members 12 and struts 14. Thestruts 14 are arranged in a plurality of diamond shapes with adjacentdiamond shapes connected to each other to form a continuous ring ofdiamond shapes around the device. One axial member 12 extends through acenter of each of the diamond shapes formed by the struts 14. A reducedthickness section 26 or hinge in each of the axial members 12 provides alocation for concentration of bending of the axial members. When anexpansion member of a deployment tool such as a rod or balloon isinserted into the tubular anastomosis device 10 and used to radiallyexpand the device, each of the diamond shaped linkages of struts 14 areelongated in a circumferential direction causing a top and bottom ofeach of the diamond shapes to move closer together. As the top andbottom of the diamond shapes move closer together, the axial members 12bend along the reduced thickness sections 26 folding the ends of thedevice outward to form the inner and outer flanges 20, 22 with theresult that the wall of the target vessel 32 is trapped between theflanges and the everted graft vessel 30 is secured to the target vessel.

In the anastomosis device 10 shown in FIGS. 1 and 2, the struts 14 maybe straight or curved members having constant or varying thicknesses. Inaddition, the axial members 12 may have the reduced thickness sections26 positioned at a center of each of the diamond shapes or off centerinside the diamond shapes. The positioning and size of the reducedthickness sections 26 will determine the location of the flanges 20, 22and an angle the flanges make with an axis of the device when fullydeployed. A final angle between the flanges 20, 22 and longitudinal axisof the device 10 is about 40-140 degrees, preferably about 50-90degrees.

FIGS. 3-7 illustrate a deployment system 150 and sequence of deployingan anastomosis device 120 such as the device shown in FIGS. 1-2 with thedeployment system. In FIGS. 3-5 the graft vessel 30 has been eliminatedfor purposes of clarity. As shown in FIGS. 3-7, the deployment system150 includes a hollow outer trocar 152 (not shown in FIG. 3), a holdertube 154 positioned inside the trocar, and an expander tube 156 slidableinside the holder tube. As can be seen in the detail of FIG. 4, theanastomosis device 120 is attached to a distal end of the holder tube154 by inserting T-shaped ends 112 of pull tabs 110 in slots 158 aroundthe circumference of the holder tube. The trocar 152, holder tube 154,and expander tube 156 are all slidable with respect to one anotherduring operation of the device. A device handle 160 is provided formoving the tubes with respect to one another will be described infurther detail below with respect to FIGS. 8-11.

As shown in FIG. 5, initially, the holder tube 154, expander tube 156,and the anastomosis device 120 are positioned within the trocar 152 forinsertion. The trocar 152 has a hollow generally conical tip with aplurality of axial slots 162 which allow the conical tip to be spreadapart so that the anastomosis device 120 can slide through the openedtrocar. The trocar 152, acting as a tissue retractor and guide, isinserted through the wall of the target vessel 32 forming an opening 34.As shown in FIG. 6, the anastomosis device 120 is then advanced into orthrough the target vessel wall 32 with the holder tube 154. Theadvancing of the holder tube 154 causes the distal end of the trocar 152to be forced to spread apart. Once the anastomosis device 120 is inposition and the trocar 152 has been withdrawn, the inner annular flange20 is deployed by advancing the expander tube 156 into the anastomosisdevice. The advancing of the expander tube 156 increases the diameter ofthe anastomosis device 120 causing the inner flange to fold outward fromthe device. This expanding of the inner flange may be performed insidethe vessel and then the device 120 may be drawn back until the innerflange abuts an interior of the target vessel wall 32.

As shown in FIG. 8, after the inner flange has been deployed, the holdertube 154 is advanced forming the outer flange. As the holder tube 154 isadvanced, the anastomosis device 120 drops into a radial groove 157 onan exterior of the expander tube 156 which holds the anastomosis devicestationary on the expander tube 156. The holder tube 154 is then movedforward to detach the entire anastomosis device by disengaging the pulltabs 130 from the slots 158 in the holder tube and causing the outerflange to be deployed. During deployment of the outer flange, shoulders134 on the device, shown most clearly in FIGS. 5 and 6, engage a tapereddistal end of the holder tube 154 causing the pull tabs 130 to bereleased from the slots 158. Alternatively, and as will be explained inconnection with a frangible anastomosis device according to theinvention, movement of the holder tube 154 can detach a deployed portionof the device from a throw away portion of the device which remainsattached to the holder tube.

One alternative embodiment of the holder tube 154 employs a plurality offlexible fingers which receive the pull tabs 130 of the anastomosisdevice 120. According to this embodiment each pull tab 130 is receivedby an independent finger of the holder tube 154. To deploy the second orouter flange of the anastomosis device 120, the flexible fingers flexoutward bending the pull tabs 130 outward.

FIGS. 9-12 illustrate the operation of the handle 160 to move the trocar152, the holder tube 154, and the expander tube 156 with respect to oneanother to deploy the anastomosis device 120 according to the presentinvention. The handle 160 includes a grip 170 and a trigger 172pivotally mounted to the grip at a pivot 174. The trigger 172 includes afinger loop 176 and three contoured cam slots 178, 180, 182corresponding to the trocar 152, holder tube 154, and expander tube 156,respectively. Each of these tubes has a fitting 184 at a distal endthereof. A pin 186 connected to each of the fittings 184 slides in acorresponding one of the cam slots 178, 180, 182. A fourth cam slot andtube may be added to control deployment of the outer flange.Alternatively, the handle can be modified to include fewer cam slots fordeployment of the inner and outer flanges.

The handle 160 is shown in FIG. 8 in an insertion position in which thetrocar 152 extends beyond the holder tube 154 and the expander tube 156for puncturing of the target vessel wall 32. Optionally, a flexible seal(not shown) such as heat shrinkable plastic tubing or a molded elastomertubing can be provided on the outer surface of the trocar 152 such thatthe seal covers the axial slots 162 at a location spaced from the tip ofthe trocar to minimize leaking of blood form the target vessel after theincision is formed. In a preferred embodiment, the trocar is actuated bya mechanism which causes the trocar to penetrate the aorta wall it ahigh rate of speed to minimize deformation of the aorta and maintain afluid tight seal at the puncture site in a manner similar to biopsy gun.For instance, the spring mechanism attached to the trocar and/or thehandle can be used to fire the trocar at the incision site. Any suitableactuating mechanism can be used to fire the trocar in accordance withthe invention. As the trigger 172 is rotated from the positionillustrated in FIG. 9 to the successive positions illustrated in FIGS.10-12, the pins 186 slide in the cam slots 178, 180, 182 to move thetrocar 152, holder tube 154 and expander tube 156.

FIG. 10 shows the handle 160 with the trigger 172 rotated approximately30 degrees from the position of FIG. 9. This rotation moves the holdertube 154 and expander tube 156 forward into the wall of the targetvessel 32 spreading the trocar 152. The anastomosis device 120 is now inposition for deployment. FIG. 11 shows the trigger 172 rotatedapproximately 45 degrees with respect to the position of FIG. 9 and thecam slot 182 has caused the expander tube 156 to be advanced within theholder tube 154 to deploy the inner flange. The trocar 152 has also beenwithdrawn.

FIG. 12 shows the handle 160 with the trigger 172 pivoted approximately60 degrees with respect to the position shown in FIG. 9. As shown inFIG. 12, the expander tube 156 has been withdrawn to pull the innerflange against the vessel wall 32 and the holder tube 154 is movedforward to deploy the outer flange and disengage the holder tube 154from the anastomosis device 120.

The handle 160 also includes a first channel 188 and a second channel190 in the grip 170 through which the graft vessel (not shown) may beguided. The grip 170 also includes a cavity 192 for protecting an end ofthe graft vessel opposite from the attachment end.

According to a preferred embodiment of the invention, the graft vesselcan be everted over the anastomosis device in the following manner.First, the graft vessel is passed through the anastomosis device whilethe anastomosis device is mounted on the deployment tool. In this“threadthrough” process, a vein graft can be positioned inside the toolsuch that it is ready for eversion (described below). The vein graftbegins this process at the back end of the tool. The threadthrough tooluses several sets of jaws to grab an end of the vein graft and draw itthrough the internal bore of the tool. The threadthrough process endswhen the vein graft has been drawn through the tool and extendsapproximately ⅛″ beyond the implant device.

In the next step, the graft vessel is folded over the anastomosisdevice. In this “eversion” process the vein graft is rolled back aroundthe implant device such that the inner surface of the vein graft isfacing away from the implant device. Eversion is achieved with aneverter tool which fits within an eversion fixture, the everter toolincluding a set of everter fingers and a drum assembly comprised of aninner drum, an outer drum, and a drum membrane. The lumen of the veingraft is placed on the cone-shaped everter fingers which then expand thevein graft to a larger diameter. The drum assembly then pins the veingraft against the implant device while the everter fingers translateforward. This forward translation causes the vein graft to roll backonto the outside of the vein graft, exposing the vein graft's innersurface. This process is now explained with reference to FIGS. 13-31.

With reference to FIGS. 13-14, in a first step, a wire or wires 402 of athreadthrough device 400 are passed through a bore 502 of a deploymenttool 500 having an anastomosis device mounted on the distal end thereof.The threadthrough tool 400 can include a plurality (e.g., two or three)threadthrough jaws 404, each of which is attached to the wire 402. As anexample, the jaws 404 can be laser cut from stainless steel tubing in amanner which provides an opening 408 in each jaw 404 and a tongue 406which lies in a plane containing a main body 410 of the jaw 404. The jaw404 can be bent at an angle ranging from 30 to 90° to the tongue 406. Inpreparation for the threadthrough process, it is advantageous for thethreadthrough tool 400 to be positioned inside the tool 500. The wire orwires 402 attached to the threadthrough jaws 404 can be inserted intothe back end of the tool 500, threaded through the internal bore 502 ofthe tool 500, and passed out through the center of the implant devicemounted on the end of the deployment tool.

As shown in FIG. 14, an eversion fixture 600 can be temporarily attachedto the front end of the tool 500. The eversion fixture can include exitchannels 602 for the threadthrough wires 402, as well as assisting theeversion process described later. Each of the threadthrough wires 402can exit the eversion fixture 600 through one or more angled exitchannels 602. The wires 402 can be pulled to draw the threadthrough jaws404 up to the back edge of the tool 500.

In the next step, a vein graft 420 is placed over the tongues 406 andinside the jaws 404, as shown in FIG. 15. The vein graft 420 can beplaced on the threadthrough tool 400 by using forceps to pull an end ofthe vein graft 420 over the tongues 406 which are clustered togetherproviding a single extension to position inside the lumen of the veingraft 420. As shown in FIG. 16, a funnel 504 having tapered channels 506at the back end of the tool 500 can be used to align the jaws 404 atequal increments apart from each other.

In the next step, the threadthrough wires 402 are pulled to draw thejaws 404 into the bore 502 of the tool 500, causing the jaws 404 toclose and grasp the vein graft 420, as shown in FIG. 17. By pulling theend of the threadthrough wires 402, the jaws 404 are drawn into the boreof the funnel 504. Inside this limited space, the jaws 404 areelastically or plastically deformed to close onto the wall of the veingraft 420. The vein graft wall is then captured between the upper jaw404 and its corresponding tongue 406. Teeth 405 along the surface of thejaws 404 facing the vein graft 420 provide additional friction toprevent the vein graft 420 from slipping out of the closed jaws 404.

Next, the wires 402, jaws 404, and vein graft 420 are pulled through thetool 500 and the implant device 430, as shown in FIG. 18. Thethreadthrough wire or wires 402, the jaws 404 and vein graft 420 aredrawn through the entire tool 500 and implant device until the jaws 404begin to exit the implant device and draw a portion of the vein graft420 out with them. The majority of the vein graft 420, however, remainsinside the bore 502 of the tool 500. As explained below, an everter 440is used to expand the end of the graft vein 420 and fold the expandedend over the outside of the device 430.

In the following step, the vein graft 420 is positioned over a conicaltip of the everter formed by a plurality of inwardly bent fingers 442extending from the end of the everter 440, as shown in FIG. 19. As shownin FIG. 20, a drum assembly 444 having a membrane 446 at the end thereofis located within the everter 440. As shown in FIG. 21, the tool 500 andthe everter 440 are located in a bore 604 of the everter fixture 600.The everter 440 and drum assembly 444 are moved along the bore 604 by ahandle 448 attached to the everter/drum assembly. In operation, as thethreadthrough wires 402 are drawn through their respective exit channels602, the grasped section of the vein graft 420 is also forced toward theexit channels 602. This causes the vein graft 420 to open over thecone-shaped fingers 442 of the everter 440. Once the jaws 404 haveemerged entirely from the implant device 430, they are then allowed tospring open, thereby releasing the vein graft 420. However, the jaws canbe removed by cutting off the portion of the vein graft attached to thejaws or manually opening the jaws. After removal of the jaws from thevein graft, the vein graft 420 is left draped around the everter fingers442 and the threadthrough wires 402 and jaws 404 are discarded.

As shown in FIG. 22, the drum assembly 444 is pushed forward while theeverter 440 and its fingers 442 remain stationary. As the drum assembly444 advances, it expands the everter fingers 442 from the cone shapeinto more of a cylinder shape which expands the vein graft 420.

Next, the drum assembly 444 and everter 440 are translated forwardtogether at the same rate, as shown in FIG. 23. As they move forwardtogether, the vein graft 420 is pushed forward into the implant device430 by the drum membrane 446. The implant device preferably includes aplurality of axially extending barbs 432, as shown in FIG. 24, at thedistal end thereof (e.g., eight circumferentially spaced apart sharpenedtips). During advancement of the membrane 444, the membrane 446 pressesagainst the axially extending tips of the implant device 430 causing thetips to penetrate the vein graft 420 and the drum membrane 446. This, ineffect, pins the vein graft 420 in between the device 430 and the drummembrane 446 at the device tips. However, the penetration of the veingraft can be omitted or achieved in other ways as will be apparent tothose skilled in the art.

In the next step, as shown in FIG. 25, the everter 440 is moved forwardwhile maintaining the drum assembly 444 stationary. Because the veingraft is pinned at the implant device tips 432, the forward motion ofthe everter fingers 442 causes the vein graft 420 to roll around thetips of the everter fingers 442, pushing the vein graft 420 off of theeverter 440 and onto the implant device 430. As shown in FIG. 26,further movement of the everter 440 causes the vein graft 420 to bepushed off of the everter 440 and onto the implant device 430. Eversionis finished once the vein graft 420 is completely off of the everterfingers 402 and only on the implant device 430, as shown in FIG. 27.After eversion is complete, the eversion hardware is removed, leavingonly the everted vein graft 420 on the implant device 430.

In the foregoing discussion, an everter fixture 600 is used to positionthe everter 440 and tool 500 during the eversion process. FIGS. 29-35show further details of a preferred fixture. As shown in FIGS. 29-30,the fixture 600 can have a cylindrical shape with view ports 606 toallow visual observation of the eversion process. As shown in FIG. 31,the fixture includes a member 610 which receives the everter 440 and abore 612 receives a forward portion 450 of the handle 448. During theeversion process, the handle 448 is pushed forward to slide the drumassembly 444 along the fingers 442 so as to expand the fingers 442 andopen the end of the graft vessel. At the same time, the rear of theeverter 440 slides into a bore 452 of the portion 450 until the evertercontacts an end wall 454 at which point the drum assembly 444 and theeverter 440 move together towards the tool 500 until the graft vessel iseverted over the device. Due to a friction fit in the bore 452, theeverter 440 is retracted along with the drum assembly 444 when thehandle 448 is pulled away from the fixture 600.

The foregoing explanation provides a description of a preferredtechnique for everting a graft vessel on an implant device. However, theeversion process can be accomplished by other less preferred techniques,some of which are discussed with reference to FIGS. 32-42.

As shown in FIG. 32, a mandrel 700 could be made in a particular shapesuch that a vein graft 702 (shown in dotted lines) is pulled andstretched over the shape of the mandrel 700. The mandrel 700 could thenbe pushed against the implant device 704 such that a proximal portion ofthe vein graft is inserted into the device and a distal end of the veingraft everted over the outside of the implant device. For instance, theshape of the mandrel can be such that the act of pushing the vein graftoff of the mandrel near the implant device will result in the vein beingeverted over the implant device.

As shown in FIGS. 33A and 33B, a mandrel 710 and collar 712 arrangementcan be used to evert a vein graft 714 over an implant device. Forinstance, an elastomeric cone 710 molded in such a way that it isbistable can be used to achieve eversion of the vein graft. Bistabilitymeans that the mandrel 710 can be deformed from one relaxed state intoanother relaxed state. In the eversion process, a vein graft 714 couldbe slid over the tip of the elastomeric cone 710 and the back of thecone could then be actuated by a cylindrical collar 712 to force thecone into its other stable mode which would appear like an invertedumbrella. In the process of changing from one configuration to the otherconfiguration, the vein graft would be everted over the implant device.

As shown in FIGS. 34A and 34B, a tube 720 could be made with severalhooks 722 around the circumference of the inside surface. These hooks722 could be attached to a hinge joint 724. A vein graft 726 loaded on amandrel 728 can be could passed through the center of the tube 720 suchthat the hooks 722 grab onto the graft 726. As the hinged hooks 722 areactuated in an outward fashion, they would evert the vein 726. The tube720 could then be pulled back, pulling the everted vein 726 over theimplant device.

As shown in FIG. 35, a vacuum fixture 730 could be used to grab and holdthe vein 732. The vacuum fixture 730 could then be manipulated to evertthe vein 732 over the device 734 at which point the vacuum could releasethe vein graft.

As shown in FIG. 36, a cylindrical mandrel 740 could be inserted intothe lumen 742 of the vein graft 744 at which point a vacuum is appliedthrough small venting holes 746 in the mandrel 740. The vacuum pressurewould affix the vein to the mandrel 740 which is then pulled into avacuum collar 747. The pressure in the mandrel 740 could then bereversed by blowing gas into the vein graft such that the pressure ofthe gas from the mandrel 740 (with or without application of vacuum bythe collar 747) results in everting the vein around the implant device748.

As shown in FIGS. 37A and 37B, an everter 750 having spreading fingers752 can be used to evert the end of the vein graft 754 over the implantdevice 756.

As shown in FIGS. 38A and 38B, a cylindrical tube 760 is made withseveral pull-tabs 762 around the circumference. Each pull-tab 762 has acorresponding hook 764 which grabs the vein graft 766 as the graft isplaced over the tube 760 and onto the hooked tabs 762. As the tabs 762are peeled back toward the implant device, the vein graft 766 can beeverted over the implant device.

As shown in FIGS. 39A and 39B, a tube 760 could be made with fingers 762that extend from the end thereof. At the end of each finger 762 is ahook 764 that protrudes toward the inside of the tube 760. This tube 760could be threaded through the implant device and then collapsed aroundthe vein graft or rotated such as by clockwise rotation such that thehooks 764 grab the outside of the vein graft. The tube 760 could then bedrawn through the device and expanded. By pushing the tube 760 backtoward the device, the vein graft can be everted over the implant deviceand by twisting the tube in a direction opposite the direction of thehooks, the vein graft can be released.

As shown in FIG. 40, a set of jaws or needles 770 on the end of longsutures 772 are threaded through the implant device and tool. The jawsor needles 770 are then affixed to the vein graft 774 at which pointvein graft 774 is drawn through the tool and device. The jaws or needles770 remain affixed to the vein graft 774 and each individual grabber orneedle 770 is pulled in an opposite direction back toward the implantdevice toward the outside. This peeling back process everts the veingraft 774 over the implant device. The vein graft material where thejaws or needles connect is then cut away leaving only the vein grafteverted over the implant device.

As shown in FIGS. 41A-E, a sleeve 780 is placed around the outside ofthe implant device 782 in order to protect it from damage. The veingraft 784 is pulled through the device and then everted around theprotective sleeve 780 using standard forceps. At this point anotherinstrument 786 could approach the implant device and cause the distaltips of the implant device 782 to be penetrated through the vein graft784. In the same motion, this secondary instrument 786 could push awaythe protective sleeve 780, leaving only the everted vein graft 784 onthe implant device 782. Alternatively, the protective sleeve can bedesigned to split apart and thus be removed by peeling it off of theimplant device.

As shown in FIG. 42, a tube 790 having a plurality of long fingers 792extending from the end of the tube 790 can be used to evert the veingraft. On each finger 792 is a small hook or barb 794 protruding towardthe outside. The fingers 792 are thread through the implant device andtool and then the vein graft 796 is placed over the fingers such thatthe barbs 794 catch the inside surface of the vein graft 796. The tube790 and its fingers 792 are then drawn through the tool and implantdevice. The fingers 792 are then expanded and pushed back around theoutside of the implant device. This forward motion of the tube 790 andits fingers 792 release the barbs 794 from the vein graft 796 allowingthe tube 790 to be retracted, and the vein graft 796 left everted on theimplant device.

Although the invention has been principally discussed with respect tocoronary bypass surgery, the anastomosis devices of the presentinvention may be used in other types of anastomosis procedures. Forexample, the anastomosis device may be used in femoral-femoral bypass,vascular shunts, subclavian-carotid bypass, organ transplants, and thelike.

The anastomosis devices may be made of any known material which can bebent and will retain the bent shape such as stainless steel, nickeltitanium alloys, and the like. The hinges or pivot joints which havebeen discussed above in the various embodiments of the present inventionmay be designed to concentrate the bending at a desired location.

While the invention has been described in detail with reference to thepreferred embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made and equivalentsemployed, without departing from the present invention.

What is claimed is:
 1. An everter tool useful for everting the end of agraft vessel over an end of an anastomosis device, the everter toolcomprising: a first member including a plurality of fingers extendingtherefrom, the fingers expandable from a first configuration in which atleast one finger is at least partially within the lumen of the graftvessel to a second configuration that expands the end of the graftvessel; a second member slidable relative to the first member; aneverter fixture including a bore; and a handle slidable relative to thebore, the handle configured to urge the second member toward theanastomosis device relative to the first member until the second memberexpands the fingers from the first configuration to the secondconfiguration, after which the handle urges the first member toward theanastomosis device.
 2. The everter tool of claim 1, further comprising adeployment tool having the anastomosis device mounted thereon and agraft vessel fitted through the anastomosis device, the anastomosisdevice being located such that the fingers can be pushed into a portionof the graft vessel extending beyond an end of the anastomosis device.3. The everter tool of claim 2, further comprising a threadthroughdevice used for locating the graft vessel within the anastomosis device,the threadthrough device configured to attach an end of the graftvessel, the threadthrough device being sized to pass through theanastomosis device.
 4. The everter tool of claim 3, wherein thethreadthrough device further includes a clamp and a tongue pivotallyconnected to the clamp, the clamp being movable towards and away fromthe tongue such that the graft vessel can be clamped between the clampand the tongue.
 5. The everter tool of claim 4, wherein thethreadthrough device includes a plurality of clamps and an extensionconnected to each of the clamps.
 6. The everter tool of claim 1, whereinthe anastomosis device includes a plurality of barbs extendingtherefrom, and wherein the everter tool includes a membrane engageablewith the anastomosis device such that the barbs penetrate the graftvessel and the membrane when the membrane is pressed against theanastomosis device.
 7. The everter tool of claim 1, wherein the evertertool includes an elastic member which is deformable from a firstconfiguration in contact with a surface of the graft vessel to a secondconfiguration which everts the graft vessel over the anastomosis deviceand wherein the anastomosis device penetrates the graft vessel and themembrane.
 8. A method of everting a graft vessel onto an anastomosisdevice, the method comprising: locating a graft vessel at leastpartially in an anastomosis device mounted on a deployment tool suchthat a first portion of the graft vessel is within the deployment tooland a second portion of the graft vessel extends from an end of thedeployment tool; expanding the second portion of the graft vessel withan everter tool; and everting the second portion of the graft vesselover the anastomosis device with the everter tool.
 9. The method ofclaim 8, wherein the step of locating the graft vessel at leastpartially in the anastomosis device is carried out by attaching an endof the graft vessel to a threadthrough device and passing thethreadthrough device through the deployment tool.
 10. The method ofclaim 8, wherein the step of expanding the second portion of the graftvessel is carried out by inserting the everter tool into the secondportion of the graft vessel.
 11. The method of claim 10, furthercomprising pressing the everter tool against the distal end of thedeployment tool until barbs on a distal end of the anastomosis devicepenetrate the graft vessel.
 12. The method of claim 10, wherein theeverter tool includes a plurality of fingers, and wherein expanding thesecond portion of the graft vessel comprises inserting the fingers intothe second portion of the graft vessel and expanding the fingers withinthe second portion of the graft vessel.
 13. The method of claim 10,wherein the step of expanding the second portion of the graft vessel iscarried out by locating the deployment tool in a bore of an everterfixture and sliding the everter tool from a first position to a secondposition along the bore.
 14. The method of claim 13, wherein the step ofeverting the second portion of the graft vessel is carried out bysliding the everter from the second position to a third position alongthe bore.
 15. The method of claim 8, wherein the step of everting thesecond portion of the graft vessel is carried out by moving the evertertool against the deployment tool.
 16. The method of claim 8, wherein thestep of locating the graft vessel in the anastomosis device is carriedout by passing the threadthrough device though the deployment tool, thethreadthrough device configured to attach to an end of the graft vessel,the threadthrough device being pulled through a hole in the fixturewhile the graft vessel is pulled through the anastomosis device.
 17. Themethod of claim 16, wherein the threadthrough device includes a clampwhich springs open after passing out of the anastomosis device leaving asegment of the graft vessel extending beyond the distal end of theanastomosis device.
 18. An everter tool configured to evert an end of agraft vessel over an end of an anastomosis device, the everter toolcomprising: a substantially tubular body; and a plurality of fingersrotatably connected to the distal end of the body, wherein each fingerrotates about a different axis and at least one axis is not parallel tothe axis of the body, the fingers expandable from a first configurationin which the fingers are at least partially received inside the graftvessel to a second configuration.
 19. The everter tool of claim 18,further comprising a poke through mechanism slidably received within thetool body.
 20. The everter tool of claim 19, wherein the poke throughmechanism includes a drum with a membrane.
 21. The everter tool of claim19, wherein at least one finger includes at least one barb for graspingthe graft vessel.
 22. The tool of claim 18, wherein the fingers are notsubstantially parallel to the axis of the lumen of the graft vessel inthe first configuration, and are substantially parallel to the axis ofthe lumen of the graft vessel in the second configuration.
 23. The toolof claim 18, wherein each finger rotates about an axis substantiallytangent to the perimeter of the distal end of the body at the locationof connection between the finger and the body.
 24. A poke through toolfor causing tips of an anastomosis device to penetrate an everted graftvessel, the poke through tool comprising: a housing configured to bereceived over a plurality of tips of the anastomosis device; and amembrane on the housing for causing the tips of the anastomosis deviceto penetrate a graft vessel and the membrane when the membrane ispressed against the graft vessel.
 25. The poke through tool according toclaim 24, wherein the membrane is aligned substantially perpendicularlywith respect to an axis of the anastomosis device.
 26. The poke throughtool according to claim 24, wherein the membrane is moved substantiallyaxially along an axial axis of the anastomosis device.
 27. The pokethrough tool according to claim 24, further comprising a stabilizationdevice disposed adjacent the membrane, wherein the stabilization deviceis adapted to receive the tips of the anastomosis device.
 28. The pokethrough tool according to claim 24, wherein the membrane is constructedof a non-elastomeric material.
 29. A method of everting a graft vesselonto an anastomosis device, the method comprising: locating a graftvessel in an anastomosis device mounted on a deployment tool such that afirst portion of the graft vessel is within the deployment tool and asecond portion of the graft vessel extends from an end of the deploymenttool, wherein locating the graft vessel in the anastomosis device iscarried out by attaching an end of the graft vessel to a threadthroughdevice and passing the threadthrough device through the deployment tool;expanding the second portion of the graft vessel with an everter tool;and everting the second portion of the graft vessel over the anastomosisdevice with the everter tool.
 30. A method of everting a graft vesselonto an anastomosis device, the method comprising: locating a graftvessel in an anastomosis device mounted on a deployment tool such that afirst portion of the graft vessel is within the deployment tool and asecond portion of the graft vessel extends from an end of the deploymenttool; expanding the second portion of the graft vessel with an evertertool by inserting the everter tool into the second portion of the graftvessel and expanding the second portion of the graft vessel by locatingthe deployment tool in a bore of an everter fixture and sliding theeverter tool from a first position to a second position along the bore;and everting the second portion of the graft vessel over the anastomosisdevice with the everter tool.
 31. The method of claim 30, wherein thestep of everting the second portion of the graft vessel is carried outby sliding the everter from the second position to a third positionalong the bore.
 32. The method of claim 30, wherein the step of locatingthe graft vessel in the anastomosis device is carried out by passing athreadthrough device though the deployment tool, the threadthroughdevice having a clamp attached to an end of the graft vessel and a wireextending from the clamp, the wire being pulled through an angled holein the fixture while the graft vessel is pulled through the anastomosisdevice.
 33. The method of claim 32, wherein the clamp springs open afterpassing out of the anastomosis device leaving a segment of the graftvessel extending beyond the distal end of the anastomosis device.